The present invention relates generally to ink jet printers of the on-demand type, and in particular to such printers having nozzle cleaning and sealing devices.
Ink jet printers of the on-demand type have been in widespread use because of their advantages in economy, noise performance and ease with which color printing can be implemented. However, one problem inherent in such on-demend type writing head is that due to the drying or thickening of residual ink in nozzle openings during non-print periods impurities tend to clog the nozzle passages or build up on nozzle surface smearing a writing surface.
An apparatus for cleaning the nozzle surface, as shown and described in U.S. Pat. No. 4,223,322, comprises a liquid-absorbing cleaning tape transported between supply and takeup reels to present a section of the tape to the nozzle surface of writing head when the latter is moved to a cleaning position during non-print period. The cleaning tape is placed against the nozzle surface of the writing head without pressure and without effecting any wiping action. The cleaning tape is held in contact with the nozzle surface for a period sufficient to permit ink to flow from the nozzles in a direction toward the cleaning medium, so that nozzle surface is wetted by liquid in which particles to be removed are dissolved. Due to the lack of wiping action, the prior art cleaning device has a low degree of efficiency and in the case of multi-color heads color mixing is likely to occur.